Arista 7280QR-C36 Load Balancing Optimization for Dual Homed Systems and Networks

Arista 7280QR-C36  The Arista DCS-7280QR-C36 switch is a purpose built flexible fixed configuration 1RU system capable of supporting a wide range of interface choices. Its designed for the highest performance environments such as IP Storage, Content Delivery Networks, Data Center Interconnect and IP Peering. The 7280QR-C36 is optimized for environments with dual connected nodes such as storage and for spine applications with dual homed leaf switches. This technical application note describes the internal optimized load-balancing mechanism used within the switch and how network architects can best deploy this system to maximize overall system performance. The internal architecture of the DCS-7280QR-C36...
Continue reading →

Load Balancing with ECMP: Hardware Configuration Lookup

Abstract: This publication illustrates a technique which can be used to find exactly how Arista devices program routes to send traffic across multiple available paths. An example will be given on the Arista DCS-7150S-52-CL-R running EOS version 4.14.8M. Initial configuration: As an IGP we are using OSPF with maximum paths feature configured: Arista(config)#router ospf 1 Arista(config-router-ospf)#maximum-paths 32 There are two iBGP peers configured via a peer-group “pg1”: Arista(config)#router bgp 65001 Arista(config-router-bgp)#neighbor pg1 maximum-routes 16000 Arista(config-router-bgp)#neighbor 172.20.18.49 peer-group pg1 Arista(config-router-bgp)#neighbor 172.20.18.121 peer-group pg1 iBGP advertisements: * >   10.82.2.32/27       172.20.16.143    0       100     0       64920 64944...
Continue reading →

BGP Multipath

BGP Multipath allows multiple next-hop entries for the same prefix to be installed in the routing table. This enables the load sharing of traffic, providing Equal Cost Multi-Pathing (ECMP) functionality. By default, BGP Multipath is disabled and the path selection algorithm will continue until one path is preferred. To enable the BGP Multipath option, the following must be configured under the BGP process: maximum-paths paths [ecmp ecmp_paths] paths  – maximum number of parallel routes in the routing table. Default value is 1. ecmp_paths – maximum number of ECMP paths stored in the forwarding table for each route. Default is maximum value. Value for...
Continue reading →

Fabric Visibility

A leaf and spine fabric is challenging to monitor. The fabric spreads traffic across all the switches and links in order to maximize bandwidth. Unlike traditional hierarchical network designs, where a small number of links can be monitored to provide visibility, a leaf and spine network has no special links or switches where running CLI commands or attaching a probe would provide visibility. Even if it were possible to attach probes, the effective bandwidth of a leaf and spine network can be as high as a Petabit/second, well beyond the capabilities of current generation monitoring tools. The 2 minute video...
Continue reading →